SSO in InAPP Browser

I implemented Azure B2C login in my React-Native application. What happening is when I try to authorise again from the app it doesn't ask me for the credentials which is expected but if I try to open a url with same tenant in InApp Browser it asks me for the credentials.
Am I missing something here because once I put in my credentials in the in App Browser it doesn't asks me again there too but why asking me for the first time when I have already logged in to the App using same tenant.